Acoustic evaluation of thermal insulation

摘要

An acoustic method for measuring the quantity and installed density of thermal insulation includes introducing a sensing apparatus comprised of one or two acoustic transducers which are so placed as to measure the attenuation and/or phase shift of acoustic waves passing through the insulation. The thermal conductivity for a given insulation material may be monitored as a function of insulation depth by relating the acoustic amplitude and/or phase to a predetermined relationship for that particular insulation material. The relationship may be simply a set of tabular guides relating the quantity of insulation to an amplitude or phase value. This method may be applied to material in an enclosed space, an attic for example where remote access would be desirable, or to material in an open space. In the case of an attic enclosure, the apparatus introduced through a small ceiling hole may be subsequently unfolded or manipulated to place the transducers and possibly a reflecting target in the desired location relative to each other for carrying out the desired measurements.